Forming tool



Jflll- 1931- w. T. PRITCHARD 8 I FORMING TOOL Filed Jan. 5, 1929 v /NVENTO/P W IPmrcmmo ATTORNEY Patented Jan. 6, 1931 UNIT srA'rEs PATENT; oF-F IcE WILLIAM r. PRITCHARD, or MAPLEWOOD, NEW JERSEY, ASSIGNOR "r BELL TELE- PHQNE LABORATORIES, INCORPORATED, or NEW YORK, in. Y., A CORPORATION or NEW YORK FORMING TOOL Application filed January 5, 1929. Serial No. 330,458. A

This invention relates to forming tools of a type which is particularly well adapted for use for adjusting the tension of switch springs used in certain telephone switching 5 apparatus. r

In selector and connector switches for ex ample, switch springs are insulatedly mounted on a common sleeve, which in turn is mounted on the switch shaft. These brushes are adapted to engage selectively and with a uniform contacting pressure terminals disposed in a number of superposed rows, which selection is effected according to the operation of the switch. When such a switch has performed a great number of operations, owing to the wear in the contacting surfaces of the switch springs and the disalignment of the springs with the terminal rows which may be due to accidental injury or to the wear in the operating parts of the switch, these switches no longer operate properly.

Heretofore it was customary to remove the switch spring units from their shafts and to replace them by new spring units.

- sion of a suitable forming tool for adjusting such switch springs in a simple and positive manner and without the necessity of removing the springs from the switch shaft.

The tool of this invention consists of a pair of pivoted handles equipped with jaws having cooperatingregistering portions between which the spring to be reformed is placed so that when pressure is applied. to the handles, the spring takes the configuration of the jaw registering portions and is simultaneously given the required tension.

In the drawings Fig. 1 is an assembly view of the tool showing the jaws in the openposition, the handle being partially cut away; Fig. 2is a partial view of the j aws'shown in the closed position with the spring in position therebetween; Fig. 3 is a partial view of a spring unit shown in perspective with one of the springs in posit-ion in the lower jaw of the tool; 7 V

Fig. s is a perspective view of a spring previous to the bending operation; and Fig. 5'is a perspective view of two cooper- The object of this invention is the provi:

ating switch springs subsequent to the forming operation. v I p In Fig. 1 of the drawings 10 and 11 are handle levers which are pivoted as at 12. Onthe efi'ective lever portions 13 and 14 of these handles thereare mounted jaw members 15 and 16 which are held in parallel relation to each other by pivots 17 and 18 and studs 19 and 20 carried by the effective lever portions and the handle members, respectively.

Jaw member 15 is ni'ounted on pivot 17 carried by the effective lever portion 14 of han dle 11" and one end of 'the' jaw is slotted for engagement with stud19 carried by handle 10. Similarly, jaw member 16"is mounted on pivot 18 carriedby the effective lever portion 13 of handle lever ;l0 and one end of this jaw is slotted for engagement with stud 20 carried byhandle lever 11. By virtue of this construction the pivotal movement of handle levers 10 and 11 from the open to the closed position or vice versa is ineffective to change the parallel relation of the jaw mem- I hers 15 and 16.

J aw'16 comprises ridges21 and 22 which form a channel provided for readily posi-' tioning the switch spring or wiper to be formedin lineparallel to the length of the cooperating jawmembers. The outward end of the ridges 21 and 22 terminate in the form' of stops 23 and 24 against which the body portion'of the'sp'ring wiper abuts. j

' Thecooperatingefl'ective or forming poreons of jaws 15 and 16 comprise two 'main cooperating plane surfaces 25 and 26, one, being that of the ridge carried by the jaw member 15 and the other that of the bottom of the channel formed by the ridges 21"and 22 carried by jaw member 16, the cooperating cam and beveled portions 27 and 28, the ridge or cam 29 and recess 30 and the cooperating concave and convexsurfaces '31 and 32 provided for bending. lug portions of the-spring outwardly to facilitate the engagement of the spring with its associated terminals in the bank. p

. In a typical example of operation after the spring has been flattened in any suitable manner, as shown in Fig. 4, the jaw 16 is inserted in a position between two'sprlngs as shown in Fig. 3 in a manner that the ends of ridges 21 and 22 engage a body portion of the switch wiper with the spring resting on the main plane surface 26 between the I guiding ridges 21 and 22. The jaws 15 and 16 are then brought together by the movement ofhandles and 11 whereby-the switch wiper is forced to take the configuration of the cooperating forming portion in. thejaws,

10 the bend imparted to the spring adjacentiits body portion being effective to give the proper tension to the spring in order to assure proper contact pressure on the terminal in the bank with which it is associated and thus avoiding further adjustment of the switch spring subsequent to the bendingoop' eration with the tool of this invention; f Applicant has discovered that a too high 7 tension of the spring onthe contact has the a 2 effect of causing the spring to wear rapidly and that insufiicient tension-of the spring on its terminalfa'ils to establish proper circuitconnection with thevconsequent interfering in the proper transmissionof speech By the useofthe tool of thisinvention, such inconvenience is efiectivelye avoided and a great amount of time is saved due to the fact that the proper forming and tensionirrg ofgthe spring are made simultaneously. is claimedis;

1. A. tool for reforming switch springs comprising a pair of 'jawinembers, actuating means therefor having means for maintaining the jaws parallel, forming and tension- 5 ing meanson said jawscomprising-two -cooperating plane surfaces extendingillongitudinally of the jaws, that on one jaw being bounded by ridges forming a channel-and thaton the other jaw being a ridge, cooper -v ating. carna -1d beveled portionson the free ends-of the-channel and rib, cooperating cam and recess portions at the endof the channel,

formed by said; plane surfaces and said" ridges, and cooperating. concave and' convex portions adjacent-said lattercam and recess portions. Y

2. A tool tor reforming .switchrwipers comprising {a pair ofp-ivotecl handles, apair ofparallel aws-mounted thereon,yforming 5d andv tensiomngl rneans on said jawsrcomprising two cooperating plane surfaces, that on one jaw being. bounded;by ridges forming-a channel and that on the other jawbeing a ridge, cam and beveled portions onrthefree '55- ends of the channel andlrib, and cooperating cam and recess portions at thfeen-d of the channel, formed by said plane-surfaces and ridges.

In witness whereof, I hereunto subscribe 0 mycnalne' this 31st day of "December, 1928'.

WILLIAM T. PRITCHARD. V 

